Coursework: Exploring low energy dwellings – retrofit & design
The overall task is to develop two integrated energy conservation packages: one for retrofitting a single energy inefficient domestic dwelling, the other is to propose a design on the same building type using modern construction materials and technologies.
2. PROJECT BRIEF
In 2012, emissions from buildings accounted for 37% of total UK greenhouse gas emissions. On a sector basis, residential emissions accounted for around 66% of total building emissions, commercial emissions for around 26% and public sector emissions for around 8%. They comprise 45% direct emissions due to the burning of fossil fuels for heat, and 55% indirect emissions related to electricity use. The key provision of the UK Climate Change Act (2008) is a legally binding commitment to cut greenhouse gas emissions by 80% by 2050, and 34% by 2020 (against a 1990 baseline). There are about 28 million homes in the UK and these houses need major work in the coming years to help reduce the UK`s carbon emissions from heating our households, with the current low built rate, 90% of them will still exist in 2050. The Paris Climate Conference (COP21) concluded with national pledges to reduce greenhouse gas emissions at rates that would limit global warming to 2oC above pre-industrial levels. It is therefore probable that meeting the carbon reduction target by 2050 will only be possible by improving the energy performance of the existing stock of the country and by reducing the carbon-based energy consumption during construction, and generating more renewable energy from distributed (localised) sources. This is not only true for the UK, but as a principle should apply to all so-called developed economies in Europe and the rest of the world.
Existing buildings can be retrofitted to help to achieve the national targets in two main ways; to be more energy efficient and to utilise lower carbon energy sources. Virtually all of the housing stock in Britain would benefit from energy improvements, but the Private Rented Sector or PRS is in most need. The PRS is the fastest growing housing sector representing more than 16% or 4.9 million houses in England 3. This is significant as the PRS has the highest proportion (11%) of houses in the lowest energy efficiency bands (those in EPC (Energy Performance Certificates) Bands F and G). This is 2% of the social housing sector. Energy inefficient housing is a direct cause of fuel poverty and almost half PRS households were in fuel poverty in 2011.
Using its powers under the Energy Act 2011, the government has drafted the ‘Private Rented Sector Energy Efficiency Regulations (Domestic) (England and
Wales). The regulations say that on 1 April 2018, ‘all eligible properties will have to be improved to a minimum energy efficiency standard before being let to tenants, except where certain exemptions apply. In addition, by 1 April 2016, tenants will have a right to request consent for energy efficiency measures that may not be unreasonably refused by the landlord.
The new build rate has been particularly low in the UK for the past decade (Fig. 1). This is often claimed as a ‘housing crisis’ as the potential housing shortage imposes challenges in finance for those who are planning to step on to the property ladder even with the government’s ‘help to buy’ scheme. From the energy perspective of new build housing, new technologies and innovative construction materials have been increasingly used to bring down the energy consumptions in homes. Technologies such as green roofs, environmental friendly insulation, biodegradable materials, rammed earth brick, water management, geothermal heating, solar power, smart appliances, etc., if integrated effectively, make achieving zero carbon housing becomes ever more realistic.
Fig 1 UK housing statistics (Source: Dept Communities & Local Government)
2.2 The Assignment
You are an energy consultant who has been asked by a private landlord to make recommendations on how the houses she owns can comply and achieve beyond new regulations. As an energy consultant with passion and interests in improving energy efficiency in dwellings you also plan to use modern materials and construction technologies to build an identical house to gain a view of how energy efficient it can be.
Task 1 – to recommend a detailed retrofit package that can help her achieve an EPC rating of B (from the current G rating). The improvement is for illustration purposes, you do not have a budget limit, however, consideration on cost effective measures are more preferable.
Task 2 – to build a house with the same massing (shape, form and size) using various passive measures, modern materials & construction techniques, renewable technologies, etc., and assess its likely energy efficiency by EPC ratings.
You need to choose one housing type from her property portfolio below for your report:
- A brick two storey semi-detached house built in the 1930’s which is now in a conservation area;
- A brick three storey terraced town house built in 1880;
- A wood-frame detached bungalow (single story) built in the 1960s.
Your report should include the following sections:
Section 1 – Introduction (10%):
- A brief introduction explaining why the work on the house needs to be done in terms of sustainable development and global warming;
- A description of why the house is so energy inefficient and what are the primary reasons the house is at such low EPC rating;
Section 2 - The EPC B upgrade (35%):
- A detailed description of the chosen measures (with appropriate illustrations of the measures or technologies) and how each measure used can be integrated into the building and how they work together to achieve a B rating (including installation details where applicable);
- A calculation that shows the annual saving to householder bills, the overall cost of the package of measures, and the annual payback over time.
Section 3 - The new build (35%):
- A detailed description of the sustainable materials and construction methods that will be used to build the new house
- An estimate of the material efficiencies, energy savings and other environmental benefits that will result from the design compared to the use of more conventional materials and practices.
- An illustration of how energy efficient your design is likely to be and what level of the energy rating (EPC rating) it can achieve from SAP (Standard Assessment Procedure) 
Section 4 - Behaviour change (10%):
This section should explain how additional energy saving might be made by the way the house is managed, and the range of ways that behaviour alone can reduce energy consumption.
2.3 Additional Information
In order to complete the economic calculation you will need to establish a typical current annual energy bill for the chosen house type. You may need to make an assumption on this, however, your assumption needs to be supported by evidence, i.e. what makes you think the energy bill is at that level by providing the reasoning.
If a measure or material is used for the new build package, and has already been described in the retrofit solution, it is acceptable to refer to this rather than write out the installation and economic implication of the measure all over again. However, all calculations must show each measure’s contribution regardless of repetition.
3. SUBMISSION REQUIREMENTS
The submission is to consist of one report of 5,000 words. The word-count excludes the Reference list which should be comprised of respected and academic sources and set out in Harvard referencing style. There should be no appendices at the end of the report.
The presentation should make clear:
1. The main technical interventions available to retrofit and new build to consume less energy. This should be communicated with the aid of drawings and diagrams showing the improvements to the building fabric and services;
2. In both the retrofit and new build, the key issues around the practical installation of the measures, and how they can combine to give an effective package of measures for different building types;
3. For the retrofit exercise, the cost implications of the package of measures with reference to typical existing energy bills, the savings that can be made after installation, and the way the Energy Performance Certificate (EPC) rating will improve as a result of the installation of the measures.
4. For the new build, what are the likely energy bills it can achieve and how technologies can help in achieving energy efficiency in dwellings.